1. Technical Field
The embodiments herein generally relate to semiconductor processing techniques, and, more particularly, to the removal of silicon nitrides during semiconductor processing.
2. Description of the Related Art
In conventional semiconductor processing systems, many dangerous chemicals are used simply because an alternative has not been found. Moreover, since these chemicals often are used for a single purpose, handling these chemicals is not only dangerous, but costly as well. For example, silicon nitrides are conventionally etched with an aqueous solution of phosphoric acid and/or nitric acid during front end of line (FEOL) processing. However, the use of phosphoric acid and/or nitric acid is generally limited to the removal of silicon nitrides. Therefore, commercial semiconductor fabrication (fab) facilities dedicate resources (e.g., equipment, workflows, personnel, etc.) within their total processing capacity in order to run these specific chemistries for the sole purpose of etching silicon nitrides during semiconductor processing.
In a conventional fab, two different chemicals are generally used for two different purposes. A sulfuric acid mixture is used for stripping photoresists, while a phosphoric acid mixture is used for etching silicon nitrides. Typically, the fab dedicates some baths in a wet-station exclusively for use with the sulfuric acid mixture and other baths exclusively for use with the phosphoric acid mixture. Accordingly, the fab also needs to maintain a supply of two different chemicals (e.g., the sulfuric acid mixture and the phosphoric acid mixture), which adds to the overall processing costs.
Therefore, if resources could be consolidated (e.g., reducing one of the chemical mixtures used during semiconductor processing), then the overall processing costs could be reduced. Accordingly, what is needed is a method that allows for the removal of common materials (e.g., silicon nitrides) used during semiconductor processing and manufacturing. By so doing, fabs can reduce the overall cost of manufacturing by reducing the conventional dependence on special purpose chemicals (e.g., phosphoric acid and/or nitric acid), reducing specific resource allocation and dedication to those special purpose chemicals, consolidating resources, and streamlining workflow operations.